To fight against Level 10+ Barbarians u must have Siege Units (Ram/Catapult/Mortar) to destroy their walls. I think 50-80 Hopites + 6 Rams is a good example. Note that u should check battle field size for your units before joining fight.

Here's a CR from 2 and a half years ago vs a level 18 Barbarian Village to give you an idea of how to efficiently smash them

Lvl 18 barbarians
Battle for Barbarian Village
(05.02.2016 7:48:48)
*** from Polis
vs
Barbarians from Polis


---------------------------------------------------------------------------------------------
............................................. - Barbarian Clubman.....................0(-275)
............................................. - Barbarian Ram..........................0(-14)
............................................. - Wall....................................0(-5)
Sulfur Carabineer.....................168(-0) - .............................................
Swordsman.............................980(-0) - .............................................
Hoplite..............................942(-14) - .............................................
Steam Giant............................80(-0) - .............................................
Gyrocopter............................163(-0) - .............................................
Balloon-Bombardier.....................15(-0) - .............................................
Ram....................................30(-0) - .............................................
Mortar.................................74(-0) - .............................................
Cook...................................60(-0) - .............................................
---------------------------------------------------------------------------------------------
Military................................-19.6 - Military....................................0
Offensive points............................0 - Defence points.............................49
Damage Received...........................980 - Damage Received.............................0
Damage Percent...........................100% - Damage Percent.............................0%

looks like u were preparing to fight against lvl 30+ barbarians that was a lot of damage

It wasn't my report, was Deagol's that I saved for reference. H ews farming really high level barbarian towns last I knew, no diea how active he is now but yeah, I've not hit barbarians for years, they strike randomly and the 25% or whatever it is reduction in production of your mines/mills on that island can be utterly devastating for me, it ends up being, if they get me when I am asleep or otherwise unable to play in a pinch, I lose hundreds of thousands of resources in lost income off the mines and mills so it isn't worth my farming them.

There was a guy that had been farming the sea maps pretty hard out but from memory the cost of those went up and it became too expensive to do, but some of the fleet battle sfor the level 40ish or whatever the high end ones were, were amazing and the loots pretty impressive to boot.

Farming the barbarians can be very profitable, but if you have high mines and mills and have the population to max out the workers on both, it can be more detrimental then beneficial. Something to keep in mind/

This is a helpful tip. Thanks. If I ever decide to spend time on the barbarians, I'll try to remember to do it only on an island where I'm not that interested in the mill and mine output.

Yeah, it's horrible when you have those days where you clonk off to sleep and get back on later then you usually would the next day and find you've lost over 200,000 or more resource income thanks to those damn barbarians. So it is a balancing act for sure.

if you're thinking about adding swords into your army, make sure you have full front line of hoplites first (150 for level 10 barbarians). swords are useful on the flanks, especially since barbarians don't add flanks until much later, but if you run out of hoplites the swords will go to the front line and die much faster than hoplites do

Well, for fighting level 10 barbarians I would usually just use 100-110 spearmen. They will however need to be fully upgraded, and forge to be active. Then you will lose 2-4 spearmen (same amount as you would with rams in addition)